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qpdf/examples/qpdfjob-c-save-attachment.c

100 lines
2.6 KiB
C

#include <qpdf/Constants.h>
#include <qpdf/qpdfjob-c.h>
#include <qpdf/qpdflogger-c.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// This example demonstrates how we can redirect where saved output
// goes by calling the default logger's setSave method before running
// something with QPDFJob. See qpdfjob-c-save-attachment.c for an
// implementation that uses the C API.
static int
save_to_file(char const* data, size_t len, void* udata)
{
FILE* f = (FILE*)udata;
return fwrite(data, 1, len, f) != len;
}
static FILE*
do_fopen(char const* filename)
{
FILE* f = NULL;
#ifdef _MSC_VER
if (fopen_s(&f, filename, "wb") != 0) {
f = NULL;
}
#else
f = fopen(filename, "wb");
#endif
if (f == NULL) {
fprintf(stderr, "unable to open %s\n", filename);
exit(2);
}
return f;
}
int
main(int argc, char* argv[])
{
char const* whoami = "qpdfjob-c-save-attachment";
char const* filename = NULL;
char const* key = NULL;
char const* outfilename = NULL;
char* attachment_arg = NULL;
char const* attachment_flag = "--show-attachment=";
size_t flag_len = 0;
FILE* outfile = NULL;
int status = 0;
qpdfjob_handle j = NULL;
qpdflogger_handle l = qpdflogger_default_logger();
if (argc != 4) {
fprintf(stderr, "Usage: %s file attachment-key outfile\n", whoami);
exit(2);
}
filename = argv[1];
key = argv[2];
outfilename = argv[3];
flag_len = strlen(attachment_flag) + strlen(key) + 1;
attachment_arg = malloc(flag_len);
#ifdef _MSC_VER
strncpy_s(attachment_arg, flag_len, attachment_flag, flag_len);
strncat_s(attachment_arg, flag_len, key, flag_len - strlen(attachment_arg));
#else
strncpy(attachment_arg, attachment_flag, flag_len);
strncat(attachment_arg, key, flag_len - strlen(attachment_arg));
#endif
char const* j_argv[5] = {
whoami,
filename,
attachment_arg,
"--",
NULL,
};
outfile = do_fopen(outfilename);
/* Use qpdflogger_set_save with a callback function to redirect
* saved data. You can use other qpdf logger functions to capture
* informational output, warnings, and errors.
*/
qpdflogger_set_save(
l, qpdf_log_dest_custom, save_to_file, (void*)outfile, 0);
qpdflogger_cleanup(&l);
j = qpdfjob_init();
status = (qpdfjob_initialize_from_argv(j, j_argv) || qpdfjob_run(j));
qpdfjob_cleanup(&j);
free(attachment_arg);
fclose(outfile);
if (status == qpdf_exit_success) {
printf("%s: wrote attachment to %s\n", whoami, outfilename);
}
return 0;
}